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Mahdouani M, Zhuri D, Sezginer Guler H, Hmida D, Sana M, Azaza M, Ben Said M, Masmoudi S, Hmila F, Youssef S, Ben Sghaier R, Brieger A, Zeuzem S, Saad A, Gurkan H, Yalcintepe S, Gribaa M, Plotz G. Functional analysis of MMR gene VUS from potential Lynch syndrome patients. PLoS One 2024; 19:e0304141. [PMID: 38843250 PMCID: PMC11156341 DOI: 10.1371/journal.pone.0304141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 05/06/2024] [Indexed: 06/09/2024] Open
Abstract
Lynch syndrome is caused by inactivating variants in DNA mismatch repair genes, namely MLH1, MSH2, MSH6 and PMS2. We have investigated five MLH1 and one MSH2 variants that we have identified in Turkish and Tunisian colorectal cancer patients. These variants comprised two small deletions causing frameshifts resulting in premature stops which could be classified pathogenic (MLH1 p.(His727Profs*57) and MSH2 p.(Thr788Asnfs*11)), but also two missense variants (MLH1 p.(Asn338Ser) and p.(Gly181Ser)) and two small, in-frame deletion variants (p.(Val647-Leu650del) and p.(Lys678_Cys680del)). For such small coding genetic variants, it is unclear if they are inactivating or not. We here provide clinical description of the variant carriers and their families, and we performed biochemical laboratory testing on the variant proteins to test if their stability or their MMR activity are compromised. Subsequently, we compared the results to in-silico predictions on structure and conservation. We demonstrate that neither missense alteration affected function, while both deletion variants caused a dramatic instability of the MLH1 protein, resulting in MMR deficiency. These results were consistent with the structural analyses that were performed. The study shows that knowledge of protein function may provide molecular explanations of results obtained with functional biochemical testing and can thereby, in conjunction with clinical information, elevate the evidential value and facilitate clinical management in affected families.
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Affiliation(s)
- Marwa Mahdouani
- Laboratory of Cytogenetics, Molecular Genetics and Human Reproduction Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia
| | - Drenushe Zhuri
- Department of Medical Genetics, Trakya University School of Medicine, Edirne, Turkey
| | - Hazal Sezginer Guler
- Department of Medical Genetics, Trakya University School of Medicine, Edirne, Turkey
| | - Dorra Hmida
- Laboratory of Cytogenetics, Molecular Genetics and Human Reproduction Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Mokni Sana
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
- Department of Dermatology and Venerology, Farhat Hached University Hospital, Sousse, Tunisia
| | - Mohamed Azaza
- Department of General Surgery, Sahloul University Hospital, Sousse, Tunisia
| | - Mariem Ben Said
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, Sfax, Tunisia
| | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, Sfax, Tunisia
| | - Fahmi Hmila
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
- Department of General and Digestive Surgery, Farhat Hached University Hospital, Sousse, Tunisia
| | - Sabri Youssef
- Department of General Surgery, Farhat Hached University Hospital, Sousse, Tunisia
| | - Rihab Ben Sghaier
- Laboratory of Cytogenetics, Molecular Genetics and Human Reproduction Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia
| | - Angela Brieger
- Biomedical Research Laboratory, Medical Clinic 1, University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Stefan Zeuzem
- Biomedical Research Laboratory, Medical Clinic 1, University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Ali Saad
- Laboratory of Cytogenetics, Molecular Genetics and Human Reproduction Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Hakan Gurkan
- Department of Medical Genetics, Trakya University School of Medicine, Edirne, Turkey
| | - Sinem Yalcintepe
- Department of Medical Genetics, Trakya University School of Medicine, Edirne, Turkey
| | - Moez Gribaa
- Laboratory of Cytogenetics, Molecular Genetics and Human Reproduction Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Guido Plotz
- Biomedical Research Laboratory, Medical Clinic 1, University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany
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Ulreich K, Firnau MB, Tagscherer N, Beyer S, Ackermann A, Plotz G, Brieger A. High Expression of Casein Kinase 2 Alpha Is Responsible for Enhanced Phosphorylation of DNA Mismatch Repair Protein MLH1 and Increased Tumor Mutation Rates in Colorectal Cancer. Cancers (Basel) 2022; 14:cancers14061553. [PMID: 35326704 PMCID: PMC8946085 DOI: 10.3390/cancers14061553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/10/2022] [Accepted: 03/15/2022] [Indexed: 02/05/2023] Open
Abstract
Simple Summary Colorectal cancer (CRC) is associated with DNA mismatch repair (MMR) deficiency. The serine/threonine casein kinase 2 alpha (CK2α) is able to phosphorylate and inhibit MMR protein MLH1 in vitro. This study aimed to analyze the relevance of CK2α for MLH1 phosphorylation in vivo. Around 50% of CRCs were identified to express significantly increased nuclear/cytoplasmic CK2α. High nuclear/cytoplasmic CK2α level could be significantly correlated with reduced 5-year survival outcome of patients, increased MLH1 phosphorylation, and enriched somatic tumor mutation rates. Overall, our study demonstrated, in vivo, that enhanced CK2α leads to an increase of MLH1 phosphorylation, higher tumor mutation rates, and is an unfavorable prognosis for patients. Abstract DNA mismatch repair (MMR) deficiency plays an essential role in the development of colorectal cancer (CRC). We recently demonstrated in vitro that the serine/threonine casein kinase 2 alpha (CK2α) causes phosphorylation of the MMR protein MLH1 at position serine 477, which significantly inhibits the MMR. In the present study, CK2α-dependent MLH1 phosphorylation was analyzed in vivo. Using a cohort of 165 patients, we identified 88 CRCs showing significantly increased nuclear/cytoplasmic CK2α expression, 28 tumors with high nuclear CK2α expression and 49 cases showing a general low CK2α expression. Patients with high nuclear/cytoplasmic CK2α expression demonstrated significantly reduced 5-year survival outcome. By immunoprecipitation and Western blot analysis, we showed that high nuclear/cytoplasmic CK2α expression significantly correlates with increased MLH1 phosphorylation and enriched somatic tumor mutation rates. The CK2α mRNA levels tended to be enhanced in high nuclear/cytoplasmic and high nuclear CK2α-expressing tumors. Furthermore, we identified various SNPs in the promotor region of CK2α, which might cause differential CK2α expression. In summary, we demonstrated that high nuclear/cytoplasmic CK2α expression in CRCs correlates with enhanced MLH1 phosphorylation in vivo and seems to be causative for increased mutation rates, presumably induced by reduced MMR. These observations could provide important new therapeutic targets.
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Liu S, Qiao W, Sun Q, Luo Y. Chromosome Region Maintenance 1 (XPO1/CRM1) as an Anticancer Target and Discovery of Its Inhibitor. J Med Chem 2021; 64:15534-15548. [PMID: 34669417 DOI: 10.1021/acs.jmedchem.1c01145] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Chromosome region maintenance 1 (CRM1) is a major nuclear export receptor protein and contributes to cell homeostasis by mediating the transport of cargo from the nucleus to the cytoplasm. CRM1 is a therapeutic target comprised of several tumor types, including osteosarcoma, multiple myeloma, gliomas, and pancreatic cancer. In the past decade, dozens of CRM1 inhibitors have been discovered and developed, including KPT-330, which received FDA approval for multiple myeloma (MM) and diffuse large B-cell lymphoma (DLBCL) in 2019 and 2020, respectively. This review summarizes the biological functions of CRM1, the current understanding of the role CRM1 plays in cancer, the discovery of CRM1 small-molecule inhibitors, preclinical and clinical studies on KPT-330, and other recently developed inhibitors. A new CRM1 inhibition mechanism and structural dynamics are discussed. Through this review, we hope to guide the future design and optimization of CRM1 inhibitors.
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Affiliation(s)
- Song Liu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Wenliang Qiao
- Lung Cancer Center, Laboratory of Lung Cancer, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Qingxiang Sun
- State Key Laboratory of Biotherapy, Department of Pathology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Youfu Luo
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
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Elez M. Mismatch Repair: From Preserving Genome Stability to Enabling Mutation Studies in Real-Time Single Cells. Cells 2021; 10:cells10061535. [PMID: 34207040 PMCID: PMC8235422 DOI: 10.3390/cells10061535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/11/2021] [Accepted: 06/15/2021] [Indexed: 12/18/2022] Open
Abstract
Mismatch Repair (MMR) is an important and conserved keeper of the maintenance of genetic information. Miroslav Radman's contributions to the field of MMR are multiple and tremendous. One of the most notable was to provide, along with Bob Wagner and Matthew Meselson, the first direct evidence for the existence of the methyl-directed MMR. The purpose of this review is to outline several aspects and biological implications of MMR that his work has helped unveil, including the role of MMR during replication and recombination editing, and the current understanding of its mechanism. The review also summarizes recent discoveries related to the visualization of MMR components and discusses how it has helped shape our understanding of the coupling of mismatch recognition to replication. Finally, the author explains how visualization of MMR components has paved the way to the study of spontaneous mutations in living cells in real time.
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Affiliation(s)
- Marina Elez
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France;
- Laboratoire Jean Perrin (LJP), Institut de Biologie Paris-Seine (IBPS), CNRS, Sorbonne Université, F-75005 Paris, France
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The Human DNA Mismatch Repair Protein MSH3 Contains Nuclear Localization and Export Signals That Enable Nuclear-Cytosolic Shuttling in Response to Inflammation. Mol Cell Biol 2020; 40:MCB.00029-20. [PMID: 32284349 DOI: 10.1128/mcb.00029-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/07/2020] [Indexed: 12/16/2022] Open
Abstract
Inactivation of DNA mismatch repair propels colorectal cancer (CRC) tumorigenesis. CRCs exhibiting elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) show reduced nuclear MutS homolog 3 (MSH3) expression with surrounding inflammation and portend poor patient outcomes. MSH3 reversibly exits from the nucleus to the cytosol in response to the proinflammatory cytokine interleukin-6 (IL-6), suggesting that MSH3 may be a shuttling protein. In this study, we manipulated three putative nuclear localization (NLS1 to -3) and two potential nuclear export signals (NES1 and -2) within MSH3. We found that both NLS1 and NLS2 possess nuclear import function, with NLS1 responsible for nuclear localization within full-length MSH3. We also found that NES1 and NES2 work synergistically to maximize nuclear export, with both being required for IL-6-induced MSH3 export. We examined a 27-bp deletion (Δ27bp) within the polymorphic exon 1 that occurs frequently in human CRC cells and neighbors NLS1. With oxidative stress, MSH3 with this deletion (Δ27bp MSH3) localizes to the cytoplasm, suggesting that NLS1 function in Δ27bp MSH3 is compromised. Overall, MSH3's shuttling in response to inflammation enables accumulation in the cytoplasm; reduced nuclear MSH3 increases EMAST and DNA damage. We suggest that polymorphic sequences adjacent to NLS1 may enhance cytosolic retention, which has clinical implications for inflammation-associated neoplastic processes.
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Lee Y, Baumhardt JM, Pei J, Chook YM, Grishin NV. pCRM1exportome: database of predicted CRM1-dependent Nuclear Export Signal (NES) motifs in cancer-related genes. Bioinformatics 2020; 36:961-963. [PMID: 31504173 PMCID: PMC8496372 DOI: 10.1093/bioinformatics/btz657] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/01/2019] [Accepted: 08/20/2019] [Indexed: 08/05/2023] Open
Abstract
MOTIVATION The consensus pattern of Nuclear Export Signal (NES) is a short sequence motif that is commonly identified in protein sequences, whether the motif acts as an NES (true positive) or not (false positive). Finding more plausible NES functioning regions among the vast array of consensus-matching segments would provide an interesting resource for further experimental validation. Better defined NES should also allow meaningful mapping of cancer-related mutation positions, leading to plausible explanations for the relationship between nuclear export and disease. RESULTS Possible NES candidate regions are extracted from the cancer-related human reference proteome. Extracted NES are scored for reliability by combining sequence-based and structure-based approaches. The confidently identified NES candidate motifs were checked for overlap with cancer-related mutation positions annotated in the COSMIC database. Among the ∼700 cancer-related sequences in the COSMIC Cancer Gene Census, 178 sequences are predicted to have possible NES motifs containing cancer-related mutations at their key positions. These lists are organized into our database (pCRM1exportome), and other protein sequences in the human reference proteome can also be retrieved by their UniProt IDs. AVAILABILITY AND IMPLEMENTATION The database is freely available at http://prodata.swmed.edu/pCRM1exportome. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
| | | | - Jimin Pei
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | | | - Nick V Grishin
- Department of Biophysics, TX 75390, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Schmidt TT, Hombauer H. Visualization of mismatch repair complexes using fluorescence microscopy. DNA Repair (Amst) 2016; 38:58-67. [DOI: 10.1016/j.dnarep.2015.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/30/2015] [Accepted: 11/30/2015] [Indexed: 11/15/2022]
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ZOU YUHUI, WANG QIONG, WANG WEIMIN. MutL homolog 1 contributes to temozolomide-induced autophagy via ataxia-telangiectasia mutated in glioma. Mol Med Rep 2015; 11:4591-6. [DOI: 10.3892/mmr.2015.3293] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 12/02/2014] [Indexed: 11/06/2022] Open
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Hinrichsen I, Ernst BP, Nuber F, Passmann S, Schäfer D, Steinke V, Friedrichs N, Plotz G, Zeuzem S, Brieger A. Reduced migration of MLH1 deficient colon cancer cells depends on SPTAN1. Mol Cancer 2014; 13:11. [PMID: 24456667 PMCID: PMC3904401 DOI: 10.1186/1476-4598-13-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 01/17/2014] [Indexed: 01/13/2023] Open
Abstract
Introduction Defects in the DNA mismatch repair (MMR) protein MLH1 are frequently observed in sporadic and hereditary colorectal cancers (CRC). Affected tumors generate much less metastatic potential than the MLH1 proficient forms. Although MLH1 has been shown to be not only involved in postreplicative MMR but also in several MMR independent processes like cytoskeletal organization, the connection between MLH1 and metastasis remains unclear. We recently identified non-erythroid spectrin αII (SPTAN1), a scaffolding protein involved in cell adhesion and motility, to interact with MLH1. In the current study, the interaction of MLH1 and SPTAN1 and its potential consequences for CRC metastasis was evaluated. Methods Nine cancer cell lines as well as fresh and paraffin embedded colon cancer tissue from 12 patients were used in gene expression studies of SPTAN1 and MLH1. Co-expression of SPTAN1 and MLH1 was analyzed by siRNA knock down of MLH1 in HeLa, HEK293, MLH1 positive HCT116, SW480 and LoVo cells. Effects on cellular motility were determined in MLH1 deficient HCT116 and MLH1 deficient HEK293T compared to their MLH1 proficient sister cells, respectively. Results MLH1 deficiency is clearly associated with SPTAN1 reduction. Moreover, siRNA knock down of MLH1 decreased the mRNA level of SPTAN1 in HeLa, HEK293 as well as in MLH1 positive HCT116 cells, which indicates a co-expression of SPTAN1 by MLH1. In addition, cellular motility of MLH1 deficient HCT116 and MLH1 deficient HEK293T cells was impaired compared to the MLH1 proficient sister clones. Consequently, overexpression of SPTAN1 increased migration of MLH1 deficient cells while knock down of SPTAN1 decreased cellular mobility of MLH1 proficient cells, indicating SPTAN1-dependent migration ability. Conclusions These data suggest that SPTAN1 levels decreased in concordance with MLH1 reduction and impaired cellular mobility in MLH1 deficient colon cancer cells. Therefore, aggressiveness of MLH1-positive CRC might be related to SPTAN1.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Angela Brieger
- Medical Clinic I, Biomedical Research Laboratory, Goethe-University, Frankfurt a,M, Germany.
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Borràs E, Pineda M, Cadiñanos J, Del Valle J, Brieger A, Hinrichsen I, Cabanillas R, Navarro M, Brunet J, Sanjuan X, Musulen E, van der Klift H, Lázaro C, Plotz G, Blanco I, Capellá G. Refining the role of PMS2 in Lynch syndrome: germline mutational analysis improved by comprehensive assessment of variants. J Med Genet 2013; 50:552-63. [PMID: 23709753 DOI: 10.1136/jmedgenet-2012-101511] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND AIM The majority of mismatch repair (MMR) gene mutations causing Lynch syndrome (LS) occur either in MLH1 or MSH2. However, the relative contribution of PMS2 is less well defined. The aim of this study was to evaluate the role of PMS2 in LS by assessing the pathogenicity of variants of unknown significance (VUS) detected in the mutational analysis of PMS2 in a series of Spanish patients. METHODS From a cohort of 202 LS suspected patients, 13 patients showing loss of PMS2 expression in tumours were screened for germline mutations in PMS2, using a long range PCR based strategy and multiplex ligation dependent probe amplification (MLPA). Pathogenicity assessment of PMS2 VUS was performed evaluating clinicopathological data, frequency in control population and in silico and in vitro analyses at the RNA and protein level. RESULTS Overall 25 different PMS2 DNA variants were detected. Fourteen were classified as polymorphisms. Nine variants were classified as pathogenic: seven alterations based on their molecular nature and two after demonstrating a functional defect (c.538-3C>G affected mRNA processing and c.137G>T impaired MMR activity). The c.1569C>G variant was classified as likely neutral while the c.384G>A remained as a VUS. We have also shown that the polymorphic variant c.59G>A is MMR proficient. CONCLUSIONS Pathogenic PMS2 mutations were detected in 69% of patients harbouring LS associated tumours with loss of PMS2 expression. In all, PMS2 mutations account for 6% of the LS cases identified. The comprehensive functional analysis shown here has been useful in the classification of PMS2 VUS and contributes to refining the role of PMS2 in LS.
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Affiliation(s)
- Ester Borràs
- Hereditary Cancer Program, Catalan Institute of Oncology, ICO-IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
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Borràs E, Pineda M, Brieger A, Hinrichsen I, Gómez C, Navarro M, Balmaña J, Ramón y Cajal T, Torres A, Brunet J, Blanco I, Plotz G, Lázaro C, Capellá G. Comprehensive functional assessment of MLH1 variants of unknown significance. Hum Mutat 2012; 33:1576-88. [PMID: 22736432 DOI: 10.1002/humu.22142] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 05/29/2012] [Indexed: 12/15/2022]
Abstract
Lynch syndrome is associated with germline mutations in DNA mismatch repair (MMR) genes. Up to 30% of DNA changes found are variants of unknown significance (VUS). Our aim was to assess the pathogenicity of eight MLH1 VUS identified in patients suspected of Lynch syndrome. All of them are novel or not previously characterized. For their classification, we followed a strategy that integrates family history, tumor pathology, and control frequency data with a variety of in silico and in vitro analyses at RNA and protein level, such as MMR assay, MLH1 and PMS2 expression, and subcellular localization. Five MLH1 VUS were classified as pathogenic: c.[248G>T(;)306G>C], c.[780C>G;788A>C], and c.791-7T>A affected mRNA processing, whereas c.218T>C (p.L73P) and c.244A>G [corrected] (p.T82A) impaired MMR activity. Two other VUS were considered likely neutral: the silent c.702G>A variant did not affect mRNA processing or stability, and c.974G>A (p.R325Q) did not influence MMR function. In contrast, variant c.25C>T (p.R9W) could not be classified, as it associated with intermediate levels of MMR activity. Comprehensive functional assessment of MLH1 variants was useful in their classification and became relevant in the diagnosis and genetic counseling of carrier families.
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Affiliation(s)
- Ester Borràs
- Hereditary Cancer Program, Catalan Institute of Oncology, ICO-IDIBELL, Hospitalet de Llobregat, Spain
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Nadin SB, Cuello-Carrión FD, Sottile ML, Ciocca DR, Vargas-Roig LM. Effects of hyperthermia on Hsp27 (HSPB1), Hsp72 (HSPA1A) and DNA repair proteins hMLH1 and hMSH2 in human colorectal cancer hMLH1-deficient and hMLH1-proficient cell lines. Int J Hyperthermia 2012; 28:191-201. [DOI: 10.3109/02656736.2011.638962] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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Shetty V, Nickens Z, Testa J, Hafner J, Sinnathamby G, Philip R. Quantitative immunoproteomics analysis reveals novel MHC class I presented peptides in cisplatin-resistant ovarian cancer cells. J Proteomics 2012; 75:3270-90. [PMID: 22504797 DOI: 10.1016/j.jprot.2012.03.044] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 03/01/2012] [Accepted: 03/25/2012] [Indexed: 10/28/2022]
Abstract
Platinum-based chemotherapy is widely used to treat various cancers including ovarian cancer. However, the mortality rate for patients with ovarian cancer is extremely high, largely due to chemo-resistant progression in patients who respond initially to platinum based chemotherapy. Immunotherapy strategies, including antigen specific vaccines, are being tested to treat drug resistant ovarian cancer with variable results. The identification of drug resistant specific tumor antigens would potentially provide significant improvement in effectiveness when combined with current and emerging therapies. In this study, using an immunoproteomics method based on iTRAQ technology and an LC-MS platform, we identified 952 MHC class I presented peptides. Quantitative analysis of the iTRAQ labeled MHC peptides revealed that cisplatin-resistant ovarian cancer cells display increased levels of MHC peptides derived from proteins that are implicated in many important cancer pathways. In addition, selected differentially presented epitope specific CTL recognize cisplatin-resistant ovarian cancer cells significantly better than the sensitive cells. These over-presented, drug resistance specific MHC class I associated peptide antigens could be potential targets for the development of immunotherapeutic strategies for the treatment of ovarian cancer including the drug resistant phenotype.
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Affiliation(s)
- Vivekananda Shetty
- Immunotope, Inc., 3805 Old Easton Road, Doylestown, PA 18902, United States.
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Brieger A, Plotz G, Hinrichsen I, Passmann S, Adam R, Zeuzem S. C-terminal fluorescent labeling impairs functionality of DNA mismatch repair proteins. PLoS One 2012; 7:e31863. [PMID: 22348133 PMCID: PMC3279419 DOI: 10.1371/journal.pone.0031863] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 01/13/2012] [Indexed: 12/22/2022] Open
Abstract
The human DNA mismatch repair (MMR) process is crucial to maintain the integrity of the genome and requires many different proteins which interact perfectly and coordinated. Germline mutations in MMR genes are responsible for the development of the hereditary form of colorectal cancer called Lynch syndrome. Various mutations mainly in two MMR proteins, MLH1 and MSH2, have been identified so far, whereas 55% are detected within MLH1, the essential component of the heterodimer MutLα (MLH1 and PMS2). Most of those MLH1 variants are pathogenic but the relevance of missense mutations often remains unclear. Many different recombinant systems are applied to filter out disease-associated proteins whereby fluorescent tagged proteins are frequently used. However, dye labeling might have deleterious effects on MutLα's functionality. Therefore, we analyzed the consequences of N- and C-terminal fluorescent labeling on expression level, cellular localization and MMR activity of MutLα. Besides significant influence of GFP- or Red-fusion on protein expression we detected incorrect shuttling of single expressed C-terminal GFP-tagged PMS2 into the nucleus and found that C-terminal dye labeling impaired MMR function of MutLα. In contrast, N-terminal tagged MutLαs retained correct functionality and can be recommended both for the analysis of cellular localization and MMR efficiency.
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Affiliation(s)
- Angela Brieger
- Department of Medicine I, University of Frankfurt/M., Frankfurt, Germany.
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